Ionic liquid based materials and catalysts for hydrogen release

Abstract

In some aspects, the present disclosure pertains to methods for the electrochemical production of hydrogen in an electrochemical cell comprising an anode, a cathode and a liquid electrolyte comprising an ionic hydrogen carrier, wherein the electrochemical cell is operated under conditions such that hydrogen gas is produced from the ionic hydrogen carrier at the cathode and wherein nitrogen gas is produced from the ionic hydrogen carrier at the anode. Other aspects pertain to devices and systems for carrying out such methods.

We claim: 
     
       1. A method for the electrochemical production of hydrogen in an electrochemical cell comprising:
 an anode; 
 a cathode; and 
 a liquid electrolyte comprising an ionic hydrogen carrier; 
 wherein the electrochemical cell is operated under conditions such that hydrogen gas is produced from the ionic hydrogen carrier at the cathode; 
 wherein nitrogen gas is produced from the ionic hydrogen carrier at the anode; and 
 wherein the electrolyte comprises at least 90 wt % of the ionic hydrogen carrier. 
 
     
     
       2. The method of  claim 1 , wherein the ionic hydrogen carrier comprises one or more anions selected from formate, acetate or nitrate anions. 
     
     
       3. The method of any of  claims 1-2 , wherein the ionic hydrogen carrier comprises one or more cations selected from ammonium, hydrazinium, or alkylammonium anions. 
     
     
       4. The method of  claim 3 , wherein hydrogen and ammonia are produced from the ammonium cation at the cathode, wherein hydrogen and hydrazine are produced from the hydrazinium cation at the cathode, or wherein hydrogen and alkyl amine are produced from alkylammonium cation at the cathode. 
     
     
       5. The method of  claim 4 , wherein nitrogen gas is produced from the ammonia at the anode, wherein nitrogen gas is produced from the hydrazine at the anode, or wherein nitrogen gas is produced from the alkylamine and water at the anode. 
     
     
       6. The method of  claim 1 , wherein nitrogen gas and water are produced from the nitrate anion at the cathode. 
     
     
       7. The method of  claim 1 , wherein carbon dioxide is produced at the anode. 
     
     
       8. The method of  claim 1 , wherein carbon dioxide gas is produced from formate anion at the anode, carbon dioxide gas is produced from acetate anion and water at the anode, or wherein carbon dioxide gas is produced from alkyl amine and water at the anode. 
     
     
       9. The method of  claim 1 , wherein the ionic hydrogen carrier is a solid at room temperature (25° C.) and the liquid electrolyte is in the form of a melt that comprises the ionic hydrogen carrier and is formed at a temperature above room temperature, wherein the ionic hydrogen carrier is a liquid at room temperature (25° C.), or wherein the ionic hydrogen carrier is a liquid at temperature (25° C.) when combined with one or more additives. 
     
     
       10. The method of  claim 1 , wherein the electrolyte comprises an additive. 
     
     
       11. The method of  claim 1 , wherein the electrolyte comprises up to 10 wt % of an additive. 
     
     
       12. The method of  claim 1 , wherein the cathode comprises a catalyst, wherein the anode comprises a catalyst, or wherein the cathode and the anode both comprise a catalyst. 
     
     
       13. The method of  claim 1 , wherein the electrochemical cell further comprises an ionically conductive separator that separates a cathode compartment containing the cathode and an anode compartment containing the anode.